Efficient picosecond optical parametric oscillator based on periodically poled lithium tantalate

Generation of transform limited picosecond pulses continuously tunable across wavelengths in the near-infrared (995–1340 nm) and midinfrared (2.1–3.6 μm) range is demonstrated in an optical parametric oscillator (OPO) based on a periodically poled stoichiometric lithium tantalate crystal. The OPO, which is synchronously pumped by a mode-locked Ti:sapphire laser, delivers about 1 W in combined average power at a repetition rate of 74 MHz, which represents close to 45% extraction efficiency in output power. With wavelength and bandwidth controlled via an intracavity diffraction grating, about 2.7 ps pulses with 3.8–10.9 cm−1 bandwidth (full width at half maximum) were generated across the tuning range in the near-infrared thus making the OPO an optimal source for use in various nonlinear spectroscopy and microscopy applications that require high spectral resolution.